If you don't know the Bentley Continental GT model by now then where have you been? All around the world you can see these brutally distinctive coupés parked where the wealthy like to show off. Ten years ago this four-seat coupé, designed by a team lead by Dirk van Braeckel, literally saved the company. Rolls-Royce Bentley, languishing with low sales and non-existent badge recognition, had been the victim of a tug-of-war battle between BMW and Volkswagen. Settled on the 19th hole of a German golf course, BMW got Rolls-Royce and Volkswagen ended up with Bentley and the factory in Crewe.

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There followed a period of massive investment and the creation of the spanking-new Continental GT model, which was parachuted into a luxury price segment where it had no rivals. It was an immediate success, cashing in on the booming property and finance sectors. Bentley production soared from a handful to almost 10,000 a year. Convertible, Speed, Supersports and a sedan version, the Flying Spur followed.

Through the crash of 2008, VW kept the faith and kept investing. The Mark II Continental GT was launched two years ago with cleaner lines, suspension revisions and a new electronic architecture courtesy of the VW central purchasing. A V-8 appeared last year, with superior handling, a little less weight and (almost) as much performance. Now we have the 2013 GT Speed version, which heralds the universal adoption of the ZF eight-speed automatic transmission across the entire Continental range plus some of the suspension revisions.

Did I mention the top speed? At 205 mph this is the world's fastest production Bentley, which is slightly strange, because while the original car had a posted v-max of 198 mph, I distinctly remember seeing the wrong side of the 200 mph mark on the launch. The answer lies in Bentley's traditional under reporting of its performance figures. So the GT Speed will do 205 mph consistently, not just with a good run up, a favorable breeze and a determined hack behind the wheel.

To get that figure, Bentley engineers have had to help up the six-liter twin turbo W-12 engine, which comprises two 15-degree angle V-6 engines on a hideously complex crankshaft. Thanks to revised software on a new Bosch ME17 engine management, the spark, fuel and boost are more carefully managed at a rate of 180 million calculations per second. Power is up to 616 bhp and torque to 590 lb.-ft. As well as the top speed, the 0-60 mph time drops to just four seconds, which is some achievement considering the car weighs 5,115 lbs. For those interested, gas mileage is 13 mpg city, 20 mpg highway and 15 mpg combined. Prices start at $215,000, although as tested our car cost a hefty $230,000. First deliveries are in November.

While the top speed is just 7 mph more than the standard W-12 Continental GT, the power required to push an object through the air increases as the cube of the velocity, so you need a lot more power to achieve a tiny increase in speed. For that reason, Bentley's engineers have not just tweaked the engine to give 49 bhp more, but they've also made the car more slippery through the air. The suspension is lowered by just less than half an inch (10mm), the underside has been smoothed and the lightweight 21-inch wheels have wind-cheating spokes. The engine's radiators and ducting have been tweaked to cool the savage beast. To keep the car on the ground at speed there's a revised deployable rear spoiler and new front-end aerodynamics. The ZF eight speed gives the required gearing to reach the top speed (an unbelievable 46 mph per 1,000 rpm) and also retains enough ratios to maintain progress at normal speeds. And, to stop this 2.3-ton behemoth, there are massive iron brake rotors and eight-piston callipers, or optional carbon ceramic brakes. The figures are simply boggling. At 205 mph the engine emits 260kW of engine heat, which is dissipated with 4,000 liters of air passing through the radiators every second. A full-power stop from that speed requires 10 mega joules of energy to be dispersed as friction heat; that's enough to light the average house for six hours.

When driving the new GT Speed, the first impression is of a slightly meaner and up-for-it stance thanks to the lower ride height, black-out grilles and front intakes, those new wheels, a strange set of `rifled' exhaust snaps and horribly arriviste `W12' badges on the front wings. Climb inside and there's the magnificence of Bentley's interior to contend with. You could spend all day simply playing with the toys. The Continental GT Mark II seats are narrower and lighter, and allow a little more room in the rear seats, but are just as comfy as the old Mark I seats. There are between nine and 10 full hides per car and it's difficult to see where they could stick much more leather, but the effect is delightfully plush. The veneers on the wing-inspired fascia design are also beautiful, although lots of customers prefer engine-turned or carbon fiber finishes for the dashboard. Much of the switchgear remains the same as the old model, including the chromium-on-aluminum "jewelry" on the dash. In all it's a brilliant mix of new and old, the new in this case including a decent new satellite navigation system and, for European customers, the long-awaited option of a Digital Audio Broadcast radio receiver. Bentley is pushing the quilted effect leather at GT Speed customers and the seats trimmed with this are comfortable and pleasingly "gentleman-racer" in appearance.

With revised algorithms for the suspension choices, the Speed model rides a slight bit more firmly whatever the setting. On smooth Munich roads of the launch that wasn't a problem, but on snow-ravaged, concrete surfaces, you're going to notice a deterioration. There's also a sports setting for the transmission, which not only leaves the gear changes quite abrupt, but the throttle more like an on/off switch, and the exhaust booming and whistling all over the cabin. Fun? Yes it is for the first couple of miles, but you quickly tire of the noise and the lack of refinement in the major controls. Even in normal mode, the transmission can hunt unpleasantly between ratios, which doesn't sit well with the idea of effortless peregrination embodied in the gran turismo badge.

Yet at high speeds, the big Bentley's stability is monumental. On wet roads, we saw a maximum of about 170 mph where the steering was rock steady with a confidence-inspiring, just-off-center response that allowed you to place it exactly on the road. Optional carbon ceramic brakes aren't the last word in linear responsiveness, but by gum they pull the car up smartly even from autobahn speeds. There wasn't a set of standard iron anchors to try on the launch, but our previous experience is that they are almost a match of the ceramics in power, with much more linearity of response.

Threaded along a twisting roads, the GT Speed has a planted feel and a pleasing reaction to the major controls, although it's still a big bruiser and the steering feels as dead as a mallet. On streaming wet roads we were glad of the permanent four-wheel drive, with its center Torsen differential and 40/60 percent front/rear torque split. If 616 bhp sounds unmanageable on a wet road then Bentley makes it simple (mostly).What happens if you drive too fast into a corner, is that the nose runs wide, then the brakes start a buzzing cadence as they try to balance each wheel to get the car straight again. Over application of the throttle results in the tail gently sliding wide, again accompanied by a bee hive's worth of brake buzzing. It's simple, gentle and easy to control, but the mass of pressurized air in the flues between the turbos and the inlet valves, can cause problems. Charge up to a corner and lift off the throttle and the engine won't start to slow for a nerve-jangling half second – on wet roads make that a terrifying half second. You become accustomed to anticipating this, but the GT Speed feels a little like a runaway locomotive as a result.

In the end all the nice bits remain just as nice on this ultimate Continental model. The cabin is an immaculate moving representation of a gentleman's club. The stability and `unstoppable force meets immovable object nature' of the performance is unlike anything else on the market, but there's a price to pay for that high top speed. The lack of refinement and nasty exhaust noise will make many wonder if Bentley hasn't forgotten what the GT letters in the Continental's name stand for.